It is known in the art to prepare diazocyano acids using a keto acid or a sodium salt of a keto acid as the starting material.
U.S. Pat. No. 4,028,345 (Moore, Jr., June 7, 1977) relates to a process comprising reacting an alphaaminonitrile selected from ##STR6## and mixtures thereof wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are selected from (1) hydrocarbyl radicals of 1 to 8 carbon atoms, (2) hydrocarbyl radicals of 1 to 8 carbon atoms substituted with carboxyl, hydroxyl or -OR wherein R is selected from a hydrocarbyl radical of 1 to 4 carbon atoms, (3) cyclohydrocarbyl radicals of 3 to 6 carbon atoms and (4) cyclohydrocarbyl radicals of 3 to 11 carbon atoms formed by combining R.sub.1 and R.sub.2 or R.sub.3 and R.sub.4 with 5 to 15 percent by weight based on the reaction mixture of a metal hypochlorite, M(OCl).sub.x, where M is selected from sodium, potassium or calcium and x is the valence of M, in an aqueous medium in the presence of 0.25 to 10 percent by weight, based on the weight of aminonitrile, of a surface active compound or mixtures thereof having an HLB of 8 to 35 at a temperature of -10.degree. C. to 30.degree. C., said hypochlorite and alpha-aminonitrile being present in an equivalent ratio of i:1 to 2:1 of hypochlorite to aminonitrile and recovering from the reaction mixture an aliphatic azonitrile of the formula ##STR7##
U.S. Pat. Nos. 4,684,717 and 4,684,718 (Ashitaka et al, Aug. 4, 1987) provide a process for the preparation of diazocyano acid, which comprises reacting a keto acid or its sodium salt with a cyanogen compound such as sodium cyanide or hydrogen cyanide and a hydrazine in water to form a concentrated aqueous solution of a hydrazo compound, adding acetone and/or water to the concentrated aqueous solution to form a solution of the hydrazo compound, adding chlorine gas to the solution to oxidize the hydrazo compound and form a diazocyano acid, and separating the diazocyano acid from the obtained reaction mixture.
U.S. Pat. No. 4,831,096 (MacLeay, May 16, 1989) relates to mixtures of azoalkanes of varying thermal stabilities, at least one of which is an unsymmetrical azoalkane (R-N=N-R'). These unsymmetrical azoalkanes are prepared by reacting four equivalents of a mixture of two or more primary alkyl, cycloalkyl or aralkyl amines with one equivalent of sulfuryl chloride in an inert solvent and oxidizing the resulting mixture of sulfamide products with basic bleach. The unsymmetrical azoalkanes can be separate from the symmetrical azoalkanes by a variety of conventional techniques. The azoalkane mixtures are polymerization initiators for vinyl monomers and curing agents for unsaturated polyester resins.